A fuel cell power plant system for a moving body includes a drive device (2) for driving the moving body by receiving power,-a power plant (10) having a fuel cell (1) for supplying power to the drive device (2) and a fuel supply device (3) which supplies fuel required by the fuel cell (1) to generate power, and a controller (6). When the moving body has stopped, the controller (6) selects one operating mode from plural operating modes according to the running state of the power plant (10), the fuel cell (1) not generating power to be supplied to the drive device in the plural operating modes, and controls the power plant (10) based on the selected operating mode.